Many foundry mold making machines have been devised to make molds of a mold material, principally sand and a binder. Usually the mold material was baked or heated in order to harden the mold to have it retain the desired shape. In recent years a thermosetting binder was utilized so that when heat was applied the resulting sand mold became quite hard. More recently cold setting mold materials were used wherein the adhesive in the sand mix was cured by passing a catalyst gas through the mold within the mold box. In both the thermosetting and the cold setting with catalyst gas processes, it was not particularly important to observe any special precautions about the already mixed sand and binder waiting in a sand magazine for the next cycle of operation. Since neither heat nor catalyst gas was applied to the sand magazine, the sand and adhesive mixture therein did not set up. As a result it was common practice to retain a fairly large quantity of sand and adhesive mixture in the magazine after each filling of the mold box.
In more recent years there has been a tendency to try to avoid use of heat in the setting of the mold within the mold box because this required energy and also made the molds and the entire mold making machine hot thereby establishing a safety hazard for workers handling the finished molds. Also in recent years there has been the desire to avoid use of the catalyst gas since most of these gasses are toxic thus presenting another safety hazard and the spent catalyst gas must be disposed of in a safe manner. If it was burned to render it non-toxic the amount of fuel gas necessary to burn the catalyst gas was as much or more than the amount of gas utilized in the thermosetting process, and was therefore also wasteful of energy.
The more recent self-setting adhesives may be ones wherein the sand was mixed with a two part liquid, a binder and catalyst, so that the complete mixture began to set or cure within a matter of seconds, e.g. ten to sixty seconds. This meant that the sand and self-setting adhesive had to be promptly moved into the mold box before it had a chance to set-up in the mixer or in the magazine. The formerly used screw type mixers were usually too slow because the sand and adhesive mixture had too long a transit time within the screw mixer. Also many machines would fill some kind of a container with a premeasured amount of sand and this container would then be moved into a blow position wherefrom it was blown into the mold box after being clamped to the mold box. All this took time for the movement of the container and the clamping and the mixture would tend to set-up in the container. Also because the mixture was usually a sticky mixture due to the liquid adhesive and catalyst, it was difficult to fill the container with a precise amount of sand and it was difficult to make sure that all of this sand was blown out of the container into the mold box. The sand mold might be either a cope or drag mold or it might be a core for use within the cope and drag mold. Where it was a core there was a special problem because if not enough sand and adhesive mixture were supplied to fill the core box, then the core would be undersize and the resulting metal casting would be oversize to wrongfully fill a desired cavity and thus the casting would be scrap rather than usable.
The quantity of sand blown from the container into the mold box was subject to many variables including the accuracy of dispensing the sand from the mixing device, the stickiness of the sand mixture and the amount of air pressure available for blowing the mixture into the mold box.
The problem to be solved therefore is to construct a molding machine which will satisfactorily mold sticky self-setting mold material in a mold box and which will be repeatable cycle after cycle in production use in a foundry. The solution to the problem is to provide a cleanable mold machine wherein the magazine and blow head is properly cleaned after each cycle of operation by a fluid directed through the magazine and out an enabled diverter passage just outboard of the blow aperture in the mold box.